Impedance balance system for gaseous discharge display panel

ABSTRACT

The disclosure is of a display system including a matrix of gas cells which can be ignited in different combinations to represent characters. In order to balance the change in impedance for the driving circuit represented by the different numbers of gas cells ignited at different times, a second similar matrix of gas cells is provided coupled to the driving circuit and operated as the negative of the first matrix; that is, when selected cells of the first matrix are ignited, the corresponding cells in the second matrix are held off and all others are ignited.

Inventor IMPEDANCE BALANCE SYSTEM FOR GASEOUS DISCHARGE DISPLAY PANEL 13Claims, 2 Drawing Figs.

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Int. Cl

States Patent Continuation of application Ser. No. 863,392, May 14,1969, now abandoned which is a continuation of application Ser. No.669,358, Sept. 15, 1967, now abandoned. This application June 18, 1970,Ser. No. 48,918

George E. 11011 [56] Reterences Cited North Plainfield, -J- UNITEDSTATES PATENTS 2,859,385 11/1958 Bentley 315/169 TV June 18, 1970Dec-28,1971 3,559,190 1/1971 Bitzeretal 315/169RUX Burroughs CorporationPrimary Examiner-John Kominski Detroit, Mich. Assistant Examiner-PalmerC. Demeo AttorneyRobert A. Green ABSTRACT: The disclosure is of adisplay system including a matrix of gas cells which can be ignited indifferent combinations to represent characters. In order to balance thechange in impedance for the driving circuit represented by the differentnumbers of gas cells ignited at different times, a second similar matrixof gas cells is provided coupled to the driving circuit and operated asthe negative of the first matrix; that is, when selected cells of thefirst matrix are ignited, the corresponding cells in the second matrixare held off and all 315/166 others are ignited.

313/210, 313/224,315/l69 TV Field of Search 315/169 R, 169 TV, 166;313/1095, 210, 224

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GEORGE E. HOLZ W m ATTORNEY IMPEDANCE BALANCE SYSTEM FOR GASEOUSDISCHARGE DISPLAY PANEL CROSS-REFERENCE TO RELATED APPLICATIONS This isa streamline continuation of application Ser. No. 863,392, filed May 14,1969, and now abandoned, which is, in turn, a continuation ofapplication Ser. No. 669,358 filed Sept. 15, 1967, and now abandoned.

BACKGROUND OF THE INVENTION This invention relates to the art of displaydevices and, particularly, to display devices of the type in which aplurality of individual display cells are energized in differentcombinations to represent different characters. Systems of this typerepresent variable impedance for the driving circuit each time thecombination of display cells is changed.

SUMMARY OF THE INVENTION DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a schematic representation of a system for operating a displaydevice comprising a matrix of gas-filled cells; and

FIG. 2 is a sectional elevational view of a portion of a display deviceshown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The system of the inventionincludes a first display panel which comprises a matrix of gas-filledcells 30, each of which can be made to glow when a suitable voltage isapplied across the cell. In a typical system, a selected group of cellscan be ignited to represent in toto a character such as a number,letter, symbol, or the like.

Essentially, a cell 30 (FIG. 2) comprises an insulating cylinder 40 ofglass or the like including an ionizable noble gas such as neon, argon,etc., or mixtures of these gases with or without other gases. A mixtureof about 94 percent neon and about 6 percent nitrogen at a pressure of afew hundred mm. Hg is particularly suitable. The gas may be introducedinto the cell in any suitable fashion, for example, through a hole inone of the end walls which is sealed after the gas has been introduced.

The cell 30 with this gas filling has memory; that is, glow onceproduced by a firing signal can be sustained after the energizing signalis removed by the application of a smaller sustaining signal. Thisphenomenon appears to be due to charges stored on the wall of theenvelope in the gas. Cell 30 has transparent glass top and bottom walls50 and 60 which carry transparent electrodes 70 and 80 of gold or thelike. Thus, the matrix of cells which make up display panel 20 maycomprise separate and distinct cells of this type, or it may be made ofa sandwich of glass plates including a central apertured plate whoseapertures form the cells and top and bottom plates. This constructionneed not be shown in detail.

Generally, the cells 30 in display device 20 are arranged in rows andcolumns, and they may be provided in any number, depending on therequired function. For convenience of illustration, three rows and threecolumns of cells are shown in the drawing. The display device or panel20 includes a common electrode 70 which is called a row electrode foreach row of cells 30, and a common electrode 80 known as a columnelectrode for each column of cells. The row electrodes 70 are all formedon one surface of the panel, and the column electrodes 80 are formed onthe opposite surface.

The display system of the invention includes a second display panel 20identical to the first and containing the same number of gas displaycells 30. Structural elements in the second panel carry the samereference numerals as the corresponding elements in the first panel butwith a prime designation.

In operation of a display panel 20 of the type shown, signals areapplied to the row and column electrodes or conductors 70 and 80, and,generally, one or more cells have the proper energizing potentialapplied across them, and these cells glow and provide the desiredcharacter representation. This type of operation of display panels isgenerally well known.

The system of the invention includes a driver circuit for the rowconductors 70 and a driver circuit for the column conductors. Circuitsof this type are generally well known and include decoders, amplifiers,and the like for receiving information in some coded form and convertingit to signals which energize the proper row and column conductors. Asource 1 12 of alternating potential which serves as a sustaining signalis also connected across all of the cells 30 of panel 20.

According to the invention, at some convenient point in the circuit, theinformation signals to be applied to the row conductors 70 are coupledthrough suitable inverter circuits to the row conductors 70' of thesecond display panel 20. Similarly, the information signals to becoupled to the column conductors of the first panel 20 are connectedthrough suitable inverter circuits 120' to the column conductors of thesecond panel 20'. The sustaining signal source 112 is also connectedacross all cells in panel 20'.

In operation of the system, driver circuits 100 and 110 produce outputswhich provide energizing potentials across selected cells in the firstdisplay panel 20. These cells are caused to glow and representinformation which can be sustained. Similarly, the reverse potentialsare applied across the corresponding cells of the second panel 20' sothat cells which glow in the first panel do not glow in the secondpanel, and vice versa. This arrangement provides a constant impedancebalance for the driver circuits 100 and 110.

What is claimed is:

l. A display system comprising a first panel including a plurality ofgas-filled cells which are adapted to glow individually and are arrayedin rows and columns in a matrix,

first electrode connections to each cell of said first panel forapplying firing potential thereto,

a second panel including a plurality of gas-filled cells which areadapted to glow individually and are arrayed in rows and columns in amatrix,

second electrode connections to each cell of said second panel forapplying firing potential thereto,

first circuit means coupling input information signals to said firstelectrode connections, and

second circuit means coupling the inverse of said information signals tosaid second electrode connections to said second panel whereby selectedcells in said first panel are caused to glow while the correspondingcells in said second panel do not glow, and

third circuit means including a source of sustaining signals coupled toboth of said panels.

2. A display system comprising a first panel including a plurality ofgas-filled cells which are adapted to glow individually and are arrayedin rows and columns,

a separate first row electrode coupled to each row of cells of saidfirst panel for applying information signals thereto,

a separate first column electrode coupled to each column of cells ofsaid first panel for applying information signals thereto,

a second panel including a plurality of gas-filled cells which areadapted to glow individually and are arrayed in rows and columns,

a separate second row electrode coupled to each row of cells of saidsecond panel for applying information signals thereto,

a separate second column electrode coupled to each column of cells ofsaid second panel for applying information signals thereto,

first circuit means coupling input information signals to said first rowand column electrodes, and

second circuit means coupling the inverse of said information signals tosaid second row and column electrodes to said second panel wherebyselected cells in said first panel are caused to glow while thecorresponding cells in said second panel do not glow, and

third circuit means including a source of sustaining signals coupled tothe row and column electrodes of said first and second panels.

3. A display system comprising a first panel having top and bottomsurfaces and including a plurality of cells filled with an ionizable gaswhich are adapted to glow individually and are arrayed in rows andcolumns,

a separate first row electrode on said top surface of said panel andcoupled to each row of cells of said first panel for applyinginformation signals thereto,

a separate first column electrode on said bottom surface of said paneland coupled to each column of cells of said first panel for applyinginformation signals thereto,

a second panel having top and bottom surfaces and including a pluralityof cells filled with an ionizable gas which are adapted to glowindividually and are arrayed in rows and columns,

a separate second row electrode connected to each row of cells of saidsecond panel for applying information signals thereto,

a separate second column electrode connected to each column of cells ofsaid second panel for applying information signals thereto,

a first drive circuit coupled to said first row electrodes and throughan inverter circuit to said second row electrodes, and

a second drive circuit coupled to said first column electrodes andthrough an inverter circuit to said second column electrodes wherebyselected cells in said first panel are caused to glow while thecorresponding cells in said second panel do not glow, and

third circuit means including a source of sustaining signals coupled tothe row and column electrodes of said first and second panels.

4. The system defined in claim 1 wherein the gas in said cells comprisesa mixture of neon and nitrogen.

5. The system defined in claim 1 wherein the gas in said cells is amixture of about 94 percent neon and about 6 percent nitrogen.

6. The system defined in claim 1 wherein the gas in said cells is amixture of about 94 percent neon and about 6 percent nitrogen at apressure of a few hundred mm. Hg.

7. The system defined in claim 1 wherein the first and second panelshave the same number of cells.

8. The system defined in claim 1 wherein the first and second panels aresubstantially identical.

9. The system defined in claim 7 wherein the impedance characteristicsof the corresponding cells of the two panels are substantially the same.

10. The system defined in claim 9 further including third circuit meanscoupled to the cells of said first and second panels, said third circuitmeans being characterized by a constant impedance characteristicsubstantially equal to that of one entire panel.

11. The system defined in claim 7 further including third circuit meansconnected to the cells of said first and second panels to supplysustaining signals to said cells, said third circuit means providing aconstant impedance characteristic for the sustaining signals.

12. The system defined in claim 11 wherein said third circuit means ischaracterized by a constant impedance characteristic substantiall e ualto that of one entire panel. I

13. The system e med in claim 1 wherem the first circuit means couplesinput information signals to n gas-filled cells in said first panel, nbeing any integer, and the second circuit means simultaneously couplesinput information signals to N-n gas-filled cells in said second panel,N signifying a predetermined integer equal to or greater than n, furtherincluding third circuit means coupled to N cells of said first andsecond panels, said third circuit means always reflecting the impedancecharacteristic of N gas-filled cells.

1. A display system comprising a first panel including a plurality ofgas-filled cells which are adapted to glow individually and are arrayedin rows and columns in a matrix, first electrode connections to eachcell of said first panel for applying firing potential thereto, a secondpanel including a plurality of gas-filled cells which are adapted toglow individually and are arrayed in rows and columns in a matrix,second electrode connections to each cell of said second panel forapplying firing potential thereto, first circuit means coupling inputinformation signals to said first electrode connections, and secondcircuit means coupling the inverse of said information signals to saidsecond electrode connections to said second panel whereby selected cellsin said first panel are caused to glow while the corresponding cells insaid second panel do noT glow, and third circuit means including asource of sustaining signals coupled to both of said panels.
 2. Adisplay system comprising a first panel including a plurality ofgas-filled cells which are adapted to glow individually and are arrayedin rows and columns, a separate first row electrode coupled to each rowof cells of said first panel for applying information signals thereto, aseparate first column electrode coupled to each column of cells of saidfirst panel for applying information signals thereto, a second panelincluding a plurality of gas-filled cells which are adapted to glowindividually and are arrayed in rows and columns, a separate second rowelectrode coupled to each row of cells of said second panel for applyinginformation signals thereto, a separate second column electrode coupledto each column of cells of said second panel for applying informationsignals thereto, first circuit means coupling input information signalsto said first row and column electrodes, and second circuit meanscoupling the inverse of said information signals to said second row andcolumn electrodes to said second panel whereby selected cells in saidfirst panel are caused to glow while the corresponding cells in saidsecond panel do not glow, and third circuit means including a source ofsustaining signals coupled to the row and column electrodes of saidfirst and second panels.
 3. A display system comprising a first panelhaving top and bottom surfaces and including a plurality of cells filledwith an ionizable gas which are adapted to glow individually and arearrayed in rows and columns, a separate first row electrode on said topsurface of said panel and coupled to each row of cells of said firstpanel for applying information signals thereto, a separate first columnelectrode on said bottom surface of said panel and coupled to eachcolumn of cells of said first panel for applying information signalsthereto, a second panel having top and bottom surfaces and including aplurality of cells filled with an ionizable gas which are adapted toglow individually and are arrayed in rows and columns, a separate secondrow electrode connected to each row of cells of said second panel forapplying information signals thereto, a separate second column electrodeconnected to each column of cells of said second panel for applyinginformation signals thereto, a first drive circuit coupled to said firstrow electrodes and through an inverter circuit to said second rowelectrodes, and a second drive circuit coupled to said first columnelectrodes and through an inverter circuit to said second columnelectrodes whereby selected cells in said first panel are caused to glowwhile the corresponding cells in said second panel do not glow, andthird circuit means including a source of sustaining signals coupled tothe row and column electrodes of said first and second panels.
 4. Thesystem defined in claim 1 wherein the gas in said cells comprises amixture of neon and nitrogen.
 5. The system defined in claim 1 whereinthe gas in said cells is a mixture of about 94 percent neon and about 6percent nitrogen.
 6. The system defined in claim 1 wherein the gas insaid cells is a mixture of about 94 percent neon and about 6 percentnitrogen at a pressure of a few hundred mm. Hg.
 7. The system defined inclaim 1 wherein the first and second panels have the same number ofcells.
 8. The system defined in claim 1 wherein the first and secondpanels are substantially identical.
 9. The system defined in claim 7wherein the impedance characteristics of the corresponding cells of thetwo panels are substantially the same.
 10. The system defined in claim 9further including third circuit means coupled to the cells of said firstand second panels, said third circuit means being characterized by aconstant impedance characteristic substantially equal to that of oneenTire panel.
 11. The system defined in claim 7 further including thirdcircuit means connected to the cells of said first and second panels tosupply sustaining signals to said cells, said third circuit meansproviding a constant impedance characteristic for the sustainingsignals.
 12. The system defined in claim 11 wherein said third circuitmeans is characterized by a constant impedance characteristicsubstantially equal to that of one entire panel.
 13. The system definedin claim 1 wherein the first circuit means couples input informationsignals to n gas-filled cells in said first panel, n being any integer,and the second circuit means simultaneously couples input informationsignals to N-n gas-filled cells in said second panel, N signifying apredetermined integer equal to or greater than n, further includingthird circuit means coupled to N cells of said first and second panels,said third circuit means always reflecting the impedance characteristicof N gas-filled cells.